Adding and subtracting whole numbers to a million

Method. Add the columns from the right. Carry any ten into the next column on the left.

1. Add the ones column. Write 8 in the ones column.
   1 + 7 = 8
2. Add the tens column. Write 1 and carry 1 to the hundreds column.
   8 + 3 = 11
3. Add the hundreds column. Write 8 in the hundreds column.
   6 + 1 + 1 carried = 8
4. Add the thousands column. Write 0 and carry 1 to the ten thousands column.
   2 + 8 = 10
5. Add the ten thousands column. Write 4 and carry 1 to the hundred thousands column.
   7 + 6 + 1 carried = 14
6. Add the hundred thousands column. Write 8 in the hundred thousands column.
   2 + 5 + 1 carried = 8
7. Write the answer. Put the digits together, with commas between groups of three.
   840,818

Check. Check: 840,818 - 568,137 = 272,681.

Watch out. Carry the 1 into the next column. Do not forget it, and do not write it as a digit in its own column.

Method. Add the columns from the right. Carry any ten into the next column on the left.

1. Add the ones column. Write 1 and carry 1 to the tens column.
   9 + 2 = 11
2. Add the tens column. Write 6 and carry 1 to the hundreds column.
   9 + 6 + 1 carried = 16
3. Add the hundreds column. Write 5 and carry 1 to the thousands column.
   9 + 5 + 1 carried = 15
4. Add the thousands column. Write 1 and carry 1 to the ten thousands column.
   9 + 1 + 1 carried = 11
5. Add the ten thousands column. Write 8 in the ten thousands column.
   2 + 5 + 1 carried = 8
6. Add the hundred thousands column. Write 6 in the hundred thousands column.
   5 + 1 = 6
7. Write the answer. Put the digits together, with commas between groups of three.
   681,561

Check. Check: 681,561 - 151,562 = 529,999.

Watch out. Carry the 1 into the next column. Do not forget it, and do not write it as a digit in its own column.

Method. Add the columns from the right. Carry any ten into the next column on the left.

1. Add the ones column. Write 3 and carry 1 to the tens column.
   5 + 8 = 13
2. Add the tens column. Write 7 and carry 1 to the hundreds column.
   7 + 9 + 1 carried = 17
3. Add the hundreds column. Write 7 in the hundreds column.
   2 + 4 + 1 carried = 7
4. Add the thousands column. Write 9 in the thousands column.
   1 + 8 = 9
5. Add the ten thousands column. Write 6 and carry 1 to the hundred thousands column.
   8 + 8 = 16
6. Add the hundred thousands column. Write 5 in the hundred thousands column.
   3 + 1 + 1 carried = 5
7. Write the answer. Put the digits together, with commas between groups of three.
   569,773

Check. Check: 569,773 - 188,498 = 381,275.

Watch out. Carry the 1 into the next column. Do not forget it, and do not write it as a digit in its own column.

Method. Add the columns from the right. Carry any ten into the next column on the left.

1. Add the ones column. Write 8 in the ones column.
   2 + 6 = 8
2. Add the tens column. Write 6 in the tens column.
   1 + 5 = 6
3. Add the hundreds column. Write 7 in the hundreds column.
   2 + 5 = 7
4. Add the thousands column. Write 4 and carry 1 to the ten thousands column.
   8 + 6 = 14
5. Add the ten thousands column. Write 2 and carry 1 to the hundred thousands column.
   2 + 9 + 1 carried = 12
6. Add the hundred thousands column. Write 9 in the hundred thousands column.
   1 + 7 + 1 carried = 9
7. Write the answer. Put the digits together, with commas between groups of three.
   924,768

Check. Check: 924,768 - 796,556 = 128,212.

Watch out. Carry the 1 into the next column. Do not forget it, and do not write it as a digit in its own column.

Method. Add the columns from the right. Carry any ten into the next column on the left.

1. Add the ones column. Write 7 in the ones column.
   6 + 1 = 7
2. Add the tens column. Write 7 in the tens column.
   2 + 5 = 7
3. Add the hundreds column. Write 9 in the hundreds column.
   7 + 2 = 9
4. Add the thousands column. Write 5 and carry 1 to the ten thousands column.
   6 + 9 = 15
5. Add the ten thousands column. Write 6 in the ten thousands column.
   3 + 2 + 1 carried = 6
6. Add the hundred thousands column. Write 9 in the hundred thousands column.
   8 + 1 = 9
7. Write the answer. Put the digits together, with commas between groups of three.
   965,977

Check. Check: 965,977 - 129,251 = 836,726.

Watch out. Carry the 1 into the next column. Do not forget it, and do not write it as a digit in its own column.

Method. Add the columns from the right. Carry any ten into the next column on the left.

1. Add the ones column. Write 1 and carry 1 to the tens column.
   5 + 6 = 11
2. Add the tens column. Write 1 and carry 1 to the hundreds column.
   7 + 3 + 1 carried = 11
3. Add the hundreds column. Write 6 in the hundreds column.
   5 + 0 + 1 carried = 6
4. Add the thousands column. Write 5 and carry 1 to the ten thousands column.
   8 + 7 = 15
5. Add the ten thousands column. Write 3 and carry 1 to the hundred thousands column.
   8 + 4 + 1 carried = 13
6. Add the hundred thousands column. Write 9 in the hundred thousands column.
   8 + 0 + 1 carried = 9
7. Write the answer. Put the digits together, with commas between groups of three.
   935,611

Check. Check: 935,611 - 47,036 = 888,575.

Watch out. Carry the 1 into the next column. Do not forget it, and do not write it as a digit in its own column.

Method. Add the columns from the right. Carry any ten into the next column on the left.

1. Add the ones column. Write 8 in the ones column.
   8 + 0 = 8
2. Add the tens column. Write 6 and carry 1 to the hundreds column.
   9 + 7 = 16
3. Add the hundreds column. Write 4 in the hundreds column.
   2 + 1 + 1 carried = 4
4. Add the thousands column. Write 9 in the thousands column.
   4 + 5 = 9
5. Add the ten thousands column. Write 5 in the ten thousands column.
   5 + 0 = 5
6. Add the hundred thousands column. Write 9 in the hundred thousands column.
   8 + 1 = 9
7. Write the answer. Put the digits together, with commas between groups of three.
   959,468

Check. Check: 959,468 - 105,170 = 854,298.

Watch out. Carry the 1 into the next column. Do not forget it, and do not write it as a digit in its own column.

Method. Add the columns from the right. Carry any ten into the next column on the left.

1. Add the ones column. Write 2 in the ones column.
   1 + 1 = 2
2. Add the tens column. Write 6 and carry 1 to the hundreds column.
   8 + 8 = 16
3. Add the hundreds column. Write 4 and carry 1 to the thousands column.
   6 + 7 + 1 carried = 14
4. Add the thousands column. Write 3 and carry 1 to the ten thousands column.
   7 + 5 + 1 carried = 13
5. Add the ten thousands column. Write 5 and carry 1 to the hundred thousands column.
   7 + 7 + 1 carried = 15
6. Add the hundred thousands column. Write 6 in the hundred thousands column.
   3 + 2 + 1 carried = 6
7. Write the answer. Put the digits together, with commas between groups of three.
   653,462

Check. Check: 653,462 - 275,781 = 377,681.

Watch out. Carry the 1 into the next column. Do not forget it, and do not write it as a digit in its own column.

Method. Add the columns from the right. Carry any ten into the next column on the left.

1. Add the ones column. Write 1 and carry 1 to the tens column.
   7 + 4 = 11
2. Add the tens column. Write 0 and carry 1 to the hundreds column.
   1 + 8 + 1 carried = 10
3. Add the hundreds column. Write 2 and carry 1 to the thousands column.
   5 + 6 + 1 carried = 12
4. Add the thousands column. Write 1 and carry 1 to the ten thousands column.
   6 + 4 + 1 carried = 11
5. Add the ten thousands column. Write 5 in the ten thousands column.
   3 + 1 + 1 carried = 5
6. Add the hundred thousands column. Write 5 in the hundred thousands column.
   1 + 4 = 5
7. Write the answer. Put the digits together, with commas between groups of three.
   551,201

Check. Check: 551,201 - 414,684 = 136,517.

Watch out. Carry the 1 into the next column. Do not forget it, and do not write it as a digit in its own column.

Method. Add the columns from the right. Carry any ten into the next column on the left.

1. Add the ones column. Write 0 and carry 1 to the tens column.
   9 + 1 = 10
2. Add the tens column. Write 8 and carry 1 to the hundreds column.
   9 + 8 + 1 carried = 18
3. Add the hundreds column. Write 5 and carry 1 to the thousands column.
   6 + 8 + 1 carried = 15
4. Add the thousands column. Write 8 in the thousands column.
   0 + 7 + 1 carried = 8
5. Add the ten thousands column. Write 7 in the ten thousands column.
   6 + 1 = 7
6. Add the hundred thousands column. Write 3 in the hundred thousands column.
   0 + 3 = 3
7. Write the answer. Put the digits together, with commas between groups of three.
   378,580

Check. Check: 378,580 - 317,881 = 60,699.

Watch out. Carry the 1 into the next column. Do not forget it, and do not write it as a digit in its own column.

Method. Add the columns from the right. Carry any ten into the next column on the left.

1. Add the ones column. Write 2 and carry 1 to the tens column.
   6 + 6 = 12
2. Add the tens column. Write 8 in the tens column.
   3 + 4 + 1 carried = 8
3. Add the hundreds column. Write 1 and carry 1 to the thousands column.
   9 + 2 = 11
4. Add the thousands column. Write 7 in the thousands column.
   0 + 6 + 1 carried = 7
5. Add the ten thousands column. Write 7 in the ten thousands column.
   4 + 3 = 7
6. Add the hundred thousands column. Write 4 in the hundred thousands column.
   2 + 2 = 4
7. Write the answer. Put the digits together, with commas between groups of three.
   477,182

Check. Check: 477,182 - 236,246 = 240,936.

Watch out. Carry the 1 into the next column. Do not forget it, and do not write it as a digit in its own column.

Method. Add the columns from the right. Carry any ten into the next column on the left.

1. Add the ones column. Write 7 in the ones column.
   0 + 7 = 7
2. Add the tens column. Write 8 in the tens column.
   5 + 3 = 8
3. Add the hundreds column. Write 0 and carry 1 to the thousands column.
   6 + 4 = 10
4. Add the thousands column. Write 9 in the thousands column.
   2 + 6 + 1 carried = 9
5. Add the ten thousands column. Write 0 and carry 1 to the hundred thousands column.
   4 + 6 = 10
6. Add the hundred thousands column. Write 8 in the hundred thousands column.
   3 + 4 + 1 carried = 8
7. Write the answer. Put the digits together, with commas between groups of three.
   809,087

Check. Check: 809,087 - 466,437 = 342,650.

Watch out. Carry the 1 into the next column. Do not forget it, and do not write it as a digit in its own column.

Method. Add the columns from the right. Carry any ten into the next column on the left.

1. Add the ones column. Write 0 and carry 1 to the tens column.
   6 + 4 = 10
2. Add the tens column. Write 8 in the tens column.
   7 + 0 + 1 carried = 8
3. Add the hundreds column. Write 6 in the hundreds column.
   3 + 3 = 6
4. Add the thousands column. Write 3 and carry 1 to the ten thousands column.
   5 + 8 = 13
5. Add the ten thousands column. Write 9 in the ten thousands column.
   7 + 1 + 1 carried = 9
6. Add the hundred thousands column. Write 9 in the hundred thousands column.
   8 + 1 = 9
7. Write the answer. Put the digits together, with commas between groups of three.
   993,680

Check. Check: 993,680 - 118,304 = 875,376.

Watch out. Carry the 1 into the next column. Do not forget it, and do not write it as a digit in its own column.

Method. Add the columns from the right. Carry any ten into the next column on the left.

1. Add the ones column. Write 0 and carry 1 to the tens column.
   1 + 9 = 10
2. Add the tens column. Write 7 and carry 1 to the hundreds column.
   9 + 7 + 1 carried = 17
3. Add the hundreds column. Write 2 and carry 1 to the thousands column.
   9 + 2 + 1 carried = 12
4. Add the thousands column. Write 5 and carry 1 to the ten thousands column.
   9 + 5 + 1 carried = 15
5. Add the ten thousands column. Write 6 in the ten thousands column.
   0 + 5 + 1 carried = 6
6. Add the hundred thousands column. Write 6 in the hundred thousands column.
   5 + 1 = 6
7. Write the answer. Put the digits together, with commas between groups of three.
   665,270

Check. Check: 665,270 - 155,279 = 509,991.

Watch out. Carry the 1 into the next column. Do not forget it, and do not write it as a digit in its own column.

Method. Add the columns from the right. Carry any ten into the next column on the left.

1. Add the ones column. Write 9 in the ones column.
   6 + 3 = 9
2. Add the tens column. Write 9 in the tens column.
   4 + 5 = 9
3. Add the hundreds column. Write 6 in the hundreds column.
   6 + 0 = 6
4. Add the thousands column. Write 7 in the thousands column.
   7 + 0 = 7
5. Add the ten thousands column. Write 6 in the ten thousands column.
   4 + 2 = 6
6. Add the hundred thousands column. Write 6 in the hundred thousands column.
   2 + 4 = 6
7. Write the answer. Put the digits together, with commas between groups of three.
   667,699

Check. Check: 667,699 - 420,053 = 247,646.

Watch out. Carry the 1 into the next column. Do not forget it, and do not write it as a digit in its own column.

Method. Add the columns from the right. Carry any ten into the next column on the left.

1. Add the ones column. Write 4 in the ones column.
   2 + 2 = 4
2. Add the tens column. Write 6 in the tens column.
   4 + 2 = 6
3. Add the hundreds column. Write 3 in the hundreds column.
   3 + 0 = 3
4. Add the thousands column. Write 0 and carry 1 to the ten thousands column.
   5 + 5 = 10
5. Add the ten thousands column. Write 3 in the ten thousands column.
   1 + 1 + 1 carried = 3
6. Add the hundred thousands column. Write 7 in the hundred thousands column.
   5 + 2 = 7
7. Write the answer. Put the digits together, with commas between groups of three.
   730,364

Check. Check: 730,364 - 215,022 = 515,342.

Watch out. Carry the 1 into the next column. Do not forget it, and do not write it as a digit in its own column.

Method. Add the columns from the right. Carry any ten into the next column on the left.

1. Add the ones column. Write 3 and carry 1 to the tens column.
   6 + 7 = 13
2. Add the tens column. Write 1 and carry 1 to the hundreds column.
   7 + 3 + 1 carried = 11
3. Add the hundreds column. Write 7 and carry 1 to the thousands column.
   9 + 7 + 1 carried = 17
4. Add the thousands column. Write 3 in the thousands column.
   2 + 0 + 1 carried = 3
5. Add the ten thousands column. Write 6 in the ten thousands column.
   0 + 6 = 6
6. Add the hundred thousands column. Write 6 in the hundred thousands column.
   4 + 2 = 6
7. Write the answer. Put the digits together, with commas between groups of three.
   663,713

Check. Check: 663,713 - 260,737 = 402,976.

Watch out. Carry the 1 into the next column. Do not forget it, and do not write it as a digit in its own column.

Method. Add the columns from the right. Carry any ten into the next column on the left.

1. Add the ones column. Write 0 and carry 1 to the tens column.
   5 + 5 = 10
2. Add the tens column. Write 2 in the tens column.
   1 + 0 + 1 carried = 2
3. Add the hundreds column. Write 5 and carry 1 to the thousands column.
   7 + 8 = 15
4. Add the thousands column. Write 8 in the thousands column.
   2 + 5 + 1 carried = 8
5. Add the ten thousands column. Write 8 in the ten thousands column.
   0 + 8 = 8
6. Add the hundred thousands column. Write 8 in the hundred thousands column.
   8 + 0 = 8
7. Write the answer. Put the digits together, with commas between groups of three.
   888,520

Check. Check: 888,520 - 85,805 = 802,715.

Watch out. Carry the 1 into the next column. Do not forget it, and do not write it as a digit in its own column.

Method. Add the columns from the right. Carry any ten into the next column on the left.

1. Add the ones column. Write 7 and carry 1 to the tens column.
   8 + 9 = 17
2. Add the tens column. Write 9 in the tens column.
   2 + 6 + 1 carried = 9
3. Add the hundreds column. Write 0 and carry 1 to the thousands column.
   4 + 6 = 10
4. Add the thousands column. Write 1 in the thousands column.
   0 + 0 + 1 carried = 1
5. Add the ten thousands column. Write 3 and carry 1 to the hundred thousands column.
   5 + 8 = 13
6. Add the hundred thousands column. Write 3 in the hundred thousands column.
   0 + 2 + 1 carried = 3
7. Write the answer. Put the digits together, with commas between groups of three.
   331,097

Check. Check: 331,097 - 280,669 = 50,428.

Watch out. Carry the 1 into the next column. Do not forget it, and do not write it as a digit in its own column.

Method. Add the columns from the right. Carry any ten into the next column on the left.

1. Add the ones column. Write 5 and carry 1 to the tens column.
   9 + 6 = 15
2. Add the tens column. Write 9 in the tens column.
   6 + 2 + 1 carried = 9
3. Add the hundreds column. Write 8 in the hundreds column.
   1 + 7 = 8
4. Add the thousands column. Write 5 and carry 1 to the ten thousands column.
   6 + 9 = 15
5. Add the ten thousands column. Write 9 in the ten thousands column.
   7 + 1 + 1 carried = 9
6. Add the hundred thousands column. Write 9 in the hundred thousands column.
   8 + 1 = 9
7. Write the answer. Put the digits together, with commas between groups of three.
   995,895

Check. Check: 995,895 - 119,726 = 876,169.

Watch out. Carry the 1 into the next column. Do not forget it, and do not write it as a digit in its own column.

Method. Add the columns from the right. Carry any ten into the next column on the left.

1. Add the ones column. Write 0 and carry 1 to the tens column.
   3 + 7 = 10
2. Add the tens column. Write 4 and carry 1 to the hundreds column.
   6 + 7 + 1 carried = 14
3. Add the hundreds column. Write 9 in the hundreds column.
   4 + 4 + 1 carried = 9
4. Add the thousands column. Write 1 and carry 1 to the ten thousands column.
   7 + 4 = 11
5. Add the ten thousands column. Write 4 and carry 1 to the hundred thousands column.
   6 + 7 + 1 carried = 14
6. Add the hundred thousands column. Write 8 in the hundred thousands column.
   7 + 0 + 1 carried = 8
7. Write the answer. Put the digits together, with commas between groups of three.
   841,940

Check. Check: 841,940 - 74,477 = 767,463.

Watch out. Carry the 1 into the next column. Do not forget it, and do not write it as a digit in its own column.

Method. Add the columns from the right. Carry any ten into the next column on the left.

1. Add the ones column. Write 0 and carry 1 to the tens column.
   8 + 2 = 10
2. Add the tens column. Write 8 in the tens column.
   5 + 2 + 1 carried = 8
3. Add the hundreds column. Write 5 and carry 1 to the thousands column.
   6 + 9 = 15
4. Add the thousands column. Write 3 and carry 1 to the ten thousands column.
   6 + 6 + 1 carried = 13
5. Add the ten thousands column. Write 4 in the ten thousands column.
   1 + 2 + 1 carried = 4
6. Add the hundred thousands column. Write 4 in the hundred thousands column.
   1 + 3 = 4
7. Write the answer. Put the digits together, with commas between groups of three.
   443,580

Check. Check: 443,580 - 326,922 = 116,658.

Watch out. Carry the 1 into the next column. Do not forget it, and do not write it as a digit in its own column.

Method. Add the columns from the right. Carry any ten into the next column on the left.

1. Add the ones column. Write 6 in the ones column.
   4 + 2 = 6
2. Add the tens column. Write 8 in the tens column.
   2 + 6 = 8
3. Add the hundreds column. Write 1 and carry 1 to the thousands column.
   7 + 4 = 11
4. Add the thousands column. Write 2 and carry 1 to the ten thousands column.
   3 + 8 + 1 carried = 12
5. Add the ten thousands column. Write 6 in the ten thousands column.
   3 + 2 + 1 carried = 6
6. Add the hundred thousands column. Write 5 in the hundred thousands column.
   5 + 0 = 5
7. Write the answer. Put the digits together, with commas between groups of three.
   562,186

Check. Check: 562,186 - 28,462 = 533,724.

Watch out. Carry the 1 into the next column. Do not forget it, and do not write it as a digit in its own column.

Method. Add the columns from the right. Carry any ten into the next column on the left.

1. Add the ones column. Write 9 in the ones column.
   6 + 3 = 9
2. Add the tens column. Write 4 in the tens column.
   2 + 2 = 4
3. Add the hundreds column. Write 0 and carry 1 to the thousands column.
   5 + 5 = 10
4. Add the thousands column. Write 0 and carry 1 to the ten thousands column.
   9 + 0 + 1 carried = 10
5. Add the ten thousands column. Write 8 in the ten thousands column.
   3 + 4 + 1 carried = 8
6. Add the hundred thousands column. Write 6 in the hundred thousands column.
   2 + 4 = 6
7. Write the answer. Put the digits together, with commas between groups of three.
   680,049

Check. Check: 680,049 - 440,523 = 239,526.

Watch out. Carry the 1 into the next column. Do not forget it, and do not write it as a digit in its own column.

Method. Add the columns from the right. Carry any ten into the next column on the left.

1. Add the ones column. Write 0 and carry 1 to the tens column.
   7 + 3 = 10
2. Add the tens column. Write 7 in the tens column.
   2 + 4 + 1 carried = 7
3. Add the hundreds column. Write 3 and carry 1 to the thousands column.
   7 + 6 = 13
4. Add the thousands column. Write 9 in the thousands column.
   8 + 0 + 1 carried = 9
5. Add the ten thousands column. Write 6 in the ten thousands column.
   6 + 0 = 6
6. Add the hundred thousands column. Write 5 in the hundred thousands column.
   2 + 3 = 5
7. Write the answer. Put the digits together, with commas between groups of three.
   569,370

Check. Check: 569,370 - 300,643 = 268,727.

Watch out. Carry the 1 into the next column. Do not forget it, and do not write it as a digit in its own column.

Method. Add the columns from the right. Carry any ten into the next column on the left.

1. Add the ones column. Write 6 in the ones column.
   1 + 5 = 6
2. Add the tens column. Write 0 and carry 1 to the hundreds column.
   7 + 3 = 10
3. Add the hundreds column. Write 3 and carry 1 to the thousands column.
   4 + 8 + 1 carried = 13
4. Add the thousands column. Write 4 and carry 1 to the ten thousands column.
   4 + 9 + 1 carried = 14
5. Add the ten thousands column. Write 2 in the ten thousands column.
   0 + 1 + 1 carried = 2
6. Add the hundred thousands column. Write 6 in the hundred thousands column.
   6 + 0 = 6
7. Write the answer. Put the digits together, with commas between groups of three.
   624,306

Check. Check: 624,306 - 19,835 = 604,471.

Watch out. Carry the 1 into the next column. Do not forget it, and do not write it as a digit in its own column.

Method. Add the columns from the right. Carry any ten into the next column on the left.

1. Add the ones column. Write 5 in the ones column.
   2 + 3 = 5
2. Add the tens column. Write 3 in the tens column.
   0 + 3 = 3
3. Add the hundreds column. Write 2 and carry 1 to the thousands column.
   6 + 6 = 12
4. Add the thousands column. Write 2 and carry 1 to the ten thousands column.
   2 + 9 + 1 carried = 12
5. Add the ten thousands column. Write 9 in the ten thousands column.
   5 + 3 + 1 carried = 9
6. Add the hundred thousands column. Write 8 in the hundred thousands column.
   5 + 3 = 8
7. Write the answer. Put the digits together, with commas between groups of three.
   892,235

Check. Check: 892,235 - 339,633 = 552,602.

Watch out. Carry the 1 into the next column. Do not forget it, and do not write it as a digit in its own column.

Method. Add the columns from the right. Carry any ten into the next column on the left.

1. Add the ones column. Write 7 and carry 1 to the tens column.
   9 + 8 = 17
2. Add the tens column. Write 9 in the tens column.
   8 + 0 + 1 carried = 9
3. Add the hundreds column. Write 9 in the hundreds column.
   6 + 3 = 9
4. Add the thousands column. Write 7 in the thousands column.
   6 + 1 = 7
5. Add the ten thousands column. Write 1 and carry 1 to the hundred thousands column.
   3 + 8 = 11
6. Add the hundred thousands column. Write 9 in the hundred thousands column.
   5 + 3 + 1 carried = 9
7. Write the answer. Put the digits together, with commas between groups of three.
   917,997

Check. Check: 917,997 - 381,308 = 536,689.

Watch out. Carry the 1 into the next column. Do not forget it, and do not write it as a digit in its own column.

Method. Add the columns from the right. Carry any ten into the next column on the left.

1. Add the ones column. Write 3 and carry 1 to the tens column.
   6 + 7 = 13
2. Add the tens column. Write 1 and carry 1 to the hundreds column.
   1 + 9 + 1 carried = 11
3. Add the hundreds column. Write 3 and carry 1 to the thousands column.
   5 + 7 + 1 carried = 13
4. Add the thousands column. Write 7 in the thousands column.
   6 + 0 + 1 carried = 7
5. Add the ten thousands column. Write 4 in the ten thousands column.
   3 + 1 = 4
6. Add the hundred thousands column. Write 8 in the hundred thousands column.
   3 + 5 = 8
7. Write the answer. Put the digits together, with commas between groups of three.
   847,313

Check. Check: 847,313 - 510,797 = 336,516.

Watch out. Carry the 1 into the next column. Do not forget it, and do not write it as a digit in its own column.

Method. Add the columns from the right. Carry any ten into the next column on the left.

1. Add the ones column. Write 4 and carry 1 to the tens column.
   9 + 5 = 14
2. Add the tens column. Write 4 and carry 1 to the hundreds column.
   5 + 8 + 1 carried = 14
3. Add the hundreds column. Write 8 in the hundreds column.
   6 + 1 + 1 carried = 8
4. Add the thousands column. Write 5 in the thousands column.
   5 + 0 = 5
5. Add the ten thousands column. Write 3 in the ten thousands column.
   0 + 3 = 3
6. Add the hundred thousands column. Write 9 in the hundred thousands column.
   8 + 1 = 9
7. Write the answer. Put the digits together, with commas between groups of three.
   935,844

Check. Check: 935,844 - 130,185 = 805,659.

Watch out. Carry the 1 into the next column. Do not forget it, and do not write it as a digit in its own column.

Method. Add the columns from the right. Carry any ten into the next column on the left.

1. Add the ones column. Write 8 in the ones column.
   7 + 1 = 8
2. Add the tens column. Write 0 and carry 1 to the hundreds column.
   4 + 6 = 10
3. Add the hundreds column. Write 2 and carry 1 to the thousands column.
   9 + 2 + 1 carried = 12
4. Add the thousands column. Write 7 in the thousands column.
   4 + 2 + 1 carried = 7
5. Add the ten thousands column. Write 1 and carry 1 to the hundred thousands column.
   3 + 8 = 11
6. Add the hundred thousands column. Write 9 in the hundred thousands column.
   5 + 3 + 1 carried = 9
7. Write the answer. Put the digits together, with commas between groups of three.
   917,208

Check. Check: 917,208 - 382,261 = 534,947.

Watch out. Carry the 1 into the next column. Do not forget it, and do not write it as a digit in its own column.

Method. Add the columns from the right. Carry any ten into the next column on the left.

1. Add the ones column. Write 1 and carry 1 to the tens column.
   8 + 3 = 11
2. Add the tens column. Write 1 in the tens column.
   0 + 0 + 1 carried = 1
3. Add the hundreds column. Write 9 in the hundreds column.
   5 + 4 = 9
4. Add the thousands column. Write 1 and carry 1 to the ten thousands column.
   3 + 8 = 11
5. Add the ten thousands column. Write 5 in the ten thousands column.
   2 + 2 + 1 carried = 5
6. Add the hundred thousands column. Write 7 in the hundred thousands column.
   7 + 0 = 7
7. Write the answer. Put the digits together, with commas between groups of three.
   751,911

Check. Check: 751,911 - 28,403 = 723,508.

Watch out. Carry the 1 into the next column. Do not forget it, and do not write it as a digit in its own column.

Method. Subtract each column from the right. Exchange 1 from the column on the left when the top digit is too small.

1. Subtract the ones column. 9 is at least 9, so subtract directly.
   9 - 9 = 0
2. Subtract the tens column. 2 is less than 8, so exchange 1 hundreds for 10 tens.
   12 - 8 = 4
3. Subtract the hundreds column. 1 is less than 2, so exchange 1 thousands for 10 hundreds.
   11 - 2 = 9
4. Subtract the thousands column. 8 is at least 0, so subtract directly.
   8 - 0 = 8
5. Subtract the ten thousands column. 1 is less than 4, so exchange 1 hundred thousands for 10 ten thousands.
   11 - 4 = 7
6. Subtract the hundred thousands column. 5 is at least 1, so subtract directly.
   5 - 1 = 4
7. Write the answer. Read the digits from the left, and put commas in.
   478,940

Check. Check: 140,289 + 478,940 = 619,229.

Watch out. When you exchange across zeros, change each zero to 9 as you pass it. Do not leave a zero in the middle.

Method. Subtract each column from the right. Exchange 1 from the column on the left when the top digit is too small.

1. Subtract the ones column. 7 is less than 8, so exchange 1 tens for 10 ones.
   17 - 8 = 9
2. Subtract the tens column. 2 is at least 1, so subtract directly.
   2 - 1 = 1
3. Subtract the hundreds column. 1 is less than 7, so exchange 1 thousands for 10 hundreds.
   11 - 7 = 4
4. Subtract the thousands column. 3 is less than 6. The ten thousands is 0, so exchange across them: take 1 hundred thousands and make each zero a 9, which gives 10 thousands.
   13 - 6 = 7
5. Subtract the ten thousands column. 9 is at least 5, so subtract directly.
   9 - 5 = 4
6. Subtract the hundred thousands column. 3 is at least 3, so subtract directly.
   3 - 3 = 0
7. Write the answer. Read the digits from the left, and put commas in.
   47,419

Check. Check: 356,718 + 47,419 = 404,137.

Watch out. When you exchange across zeros, change each zero to 9 as you pass it. Do not leave a zero in the middle.

Method. Subtract each column from the right. Exchange 1 from the column on the left when the top digit is too small.

1. Subtract the ones column. 5 is less than 6, so exchange 1 tens for 10 ones.
   15 - 6 = 9
2. Subtract the tens column. 3 is less than 8. The hundreds is 0, so exchange across them: take 1 thousands and make each zero a 9, which gives 10 tens.
   13 - 8 = 5
3. Subtract the hundreds column. 9 is at least 5, so subtract directly.
   9 - 5 = 4
4. Subtract the thousands column. 5 is less than 7, so exchange 1 ten thousands for 10 thousands.
   15 - 7 = 8
5. Subtract the ten thousands column. 7 is less than 9, so exchange 1 hundred thousands for 10 ten thousands.
   17 - 9 = 8
6. Subtract the hundred thousands column. 6 is at least 5, so subtract directly.
   6 - 5 = 1
7. Write the answer. Read the digits from the left, and put commas in.
   188,459

Check. Check: 597,586 + 188,459 = 786,045.

Watch out. When you exchange across zeros, change each zero to 9 as you pass it. Do not leave a zero in the middle.

Method. Subtract each column from the right. Exchange 1 from the column on the left when the top digit is too small.

1. Subtract the ones column. 1 is less than 8, so exchange 1 tens for 10 ones.
   11 - 8 = 3
2. Subtract the tens column. 2 is at least 1, so subtract directly.
   2 - 1 = 1
3. Subtract the hundreds column. 2 is less than 8, so exchange 1 thousands for 10 hundreds.
   12 - 8 = 4
4. Subtract the thousands column. 2 is less than 9, so exchange 1 ten thousands for 10 thousands.
   12 - 9 = 3
5. Subtract the ten thousands column. 3 is at least 3, so subtract directly.
   3 - 3 = 0
6. Subtract the hundred thousands column. 6 is at least 1, so subtract directly.
   6 - 1 = 5
7. Write the answer. Read the digits from the left, and put commas in.
   503,413

Check. Check: 139,818 + 503,413 = 643,231.

Watch out. When you exchange across zeros, change each zero to 9 as you pass it. Do not leave a zero in the middle.

Method. Subtract each column from the right. Exchange 1 from the column on the left when the top digit is too small.

1. Subtract the ones column. 6 is at least 6, so subtract directly.
   6 - 6 = 0
2. Subtract the tens column. 0 is less than 2, so exchange 1 hundreds for 10 tens.
   10 - 2 = 8
3. Subtract the hundreds column. 2 is less than 3, so exchange 1 thousands for 10 hundreds.
   12 - 3 = 9
4. Subtract the thousands column. 6 is at least 0, so subtract directly.
   6 - 0 = 6
5. Subtract the ten thousands column. 7 is less than 8, so exchange 1 hundred thousands for 10 ten thousands.
   17 - 8 = 9
6. Subtract the hundred thousands column. 3 is at least 3, so subtract directly.
   3 - 3 = 0
7. Write the answer. Read the digits from the left, and put commas in.
   96,980

Check. Check: 380,326 + 96,980 = 477,306.

Watch out. When you exchange across zeros, change each zero to 9 as you pass it. Do not leave a zero in the middle.

Method. Subtract each column from the right. Exchange 1 from the column on the left when the top digit is too small.

1. Subtract the ones column. 7 is at least 3, so subtract directly.
   7 - 3 = 4
2. Subtract the tens column. 2 is less than 8, so exchange 1 hundreds for 10 tens.
   12 - 8 = 4
3. Subtract the hundreds column. 4 is at least 2, so subtract directly.
   4 - 2 = 2
4. Subtract the thousands column. 9 is at least 2, so subtract directly.
   9 - 2 = 7
5. Subtract the ten thousands column. 4 is less than 5, so exchange 1 hundred thousands for 10 ten thousands.
   14 - 5 = 9
6. Subtract the hundred thousands column. 8 is at least 0, so subtract directly.
   8 - 0 = 8
7. Write the answer. Read the digits from the left, and put commas in.
   897,244

Check. Check: 52,283 + 897,244 = 949,527.

Watch out. When you exchange across zeros, change each zero to 9 as you pass it. Do not leave a zero in the middle.

Method. Subtract each column from the right. Exchange 1 from the column on the left when the top digit is too small.

1. Subtract the ones column. 3 is at least 1, so subtract directly.
   3 - 1 = 2
2. Subtract the tens column. 7 is at least 1, so subtract directly.
   7 - 1 = 6
3. Subtract the hundreds column. 5 is less than 6, so exchange 1 thousands for 10 hundreds.
   15 - 6 = 9
4. Subtract the thousands column. 8 is at least 7, so subtract directly.
   8 - 7 = 1
5. Subtract the ten thousands column. 9 is at least 5, so subtract directly.
   9 - 5 = 4
6. Subtract the hundred thousands column. 7 is at least 6, so subtract directly.
   7 - 6 = 1
7. Write the answer. Read the digits from the left, and put commas in.
   141,962

Check. Check: 657,611 + 141,962 = 799,573.

Watch out. When you exchange across zeros, change each zero to 9 as you pass it. Do not leave a zero in the middle.

Method. Subtract each column from the right. Exchange 1 from the column on the left when the top digit is too small.

1. Subtract the ones column. 9 is at least 4, so subtract directly.
   9 - 4 = 5
2. Subtract the tens column. 7 is at least 6, so subtract directly.
   7 - 6 = 1
3. Subtract the hundreds column. 0 is less than 4, so exchange 1 thousands for 10 hundreds.
   10 - 4 = 6
4. Subtract the thousands column. 7 is at least 5, so subtract directly.
   7 - 5 = 2
5. Subtract the ten thousands column. 5 is less than 6, so exchange 1 hundred thousands for 10 ten thousands.
   15 - 6 = 9
6. Subtract the hundred thousands column. 3 is at least 0, so subtract directly.
   3 - 0 = 3
7. Write the answer. Read the digits from the left, and put commas in.
   392,615

Check. Check: 65,464 + 392,615 = 458,079.

Watch out. When you exchange across zeros, change each zero to 9 as you pass it. Do not leave a zero in the middle.

Method. Subtract each column from the right. Exchange 1 from the column on the left when the top digit is too small.

1. Subtract the ones column. 7 is at least 4, so subtract directly.
   7 - 4 = 3
2. Subtract the tens column. 9 is at least 7, so subtract directly.
   9 - 7 = 2
3. Subtract the hundreds column. 2 is less than 9. The thousands is 0, so exchange across them: take 1 ten thousands and make each zero a 9, which gives 10 hundreds.
   12 - 9 = 3
4. Subtract the thousands column. 9 is at least 2, so subtract directly.
   9 - 2 = 7
5. Subtract the ten thousands column. 2 is less than 7, so exchange 1 hundred thousands for 10 ten thousands.
   12 - 7 = 5
6. Subtract the hundred thousands column. 6 is at least 0, so subtract directly.
   6 - 0 = 6
7. Write the answer. Read the digits from the left, and put commas in.
   657,323

Check. Check: 72,974 + 657,323 = 730,297.

Watch out. When you exchange across zeros, change each zero to 9 as you pass it. Do not leave a zero in the middle.

Method. Subtract each column from the right. Exchange 1 from the column on the left when the top digit is too small.

1. Subtract the ones column. 9 is at least 6, so subtract directly.
   9 - 6 = 3
2. Subtract the tens column. 1 is less than 7, so exchange 1 hundreds for 10 tens.
   11 - 7 = 4
3. Subtract the hundreds column. 7 is at least 2, so subtract directly.
   7 - 2 = 5
4. Subtract the thousands column. 3 is less than 5, so exchange 1 ten thousands for 10 thousands.
   13 - 5 = 8
5. Subtract the ten thousands column. 6 is at least 6, so subtract directly.
   6 - 6 = 0
6. Subtract the hundred thousands column. 2 is at least 1, so subtract directly.
   2 - 1 = 1
7. Write the answer. Read the digits from the left, and put commas in.
   108,543

Check. Check: 165,276 + 108,543 = 273,819.

Watch out. When you exchange across zeros, change each zero to 9 as you pass it. Do not leave a zero in the middle.

Method. Subtract each column from the right. Exchange 1 from the column on the left when the top digit is too small.

1. Subtract the ones column. 4 is at least 3, so subtract directly.
   4 - 3 = 1
2. Subtract the tens column. 7 is at least 7, so subtract directly.
   7 - 7 = 0
3. Subtract the hundreds column. 5 is at least 0, so subtract directly.
   5 - 0 = 5
4. Subtract the thousands column. 5 is less than 6, so exchange 1 ten thousands for 10 thousands.
   15 - 6 = 9
5. Subtract the ten thousands column. 0 is less than 1, so exchange 1 hundred thousands for 10 ten thousands.
   10 - 1 = 9
6. Subtract the hundred thousands column. 5 is at least 5, so subtract directly.
   5 - 5 = 0
7. Write the answer. Read the digits from the left, and put commas in.
   99,501

Check. Check: 516,073 + 99,501 = 615,574.

Watch out. When you exchange across zeros, change each zero to 9 as you pass it. Do not leave a zero in the middle.

Method. Subtract each column from the right. Exchange 1 from the column on the left when the top digit is too small.

1. Subtract the ones column. 7 is at least 0, so subtract directly.
   7 - 0 = 7
2. Subtract the tens column. 4 is less than 6, so exchange 1 hundreds for 10 tens.
   14 - 6 = 8
3. Subtract the hundreds column. 3 is less than 8, so exchange 1 thousands for 10 hundreds.
   13 - 8 = 5
4. Subtract the thousands column. 5 is less than 8, so exchange 1 ten thousands for 10 thousands.
   15 - 8 = 7
5. Subtract the ten thousands column. 7 is at least 6, so subtract directly.
   7 - 6 = 1
6. Subtract the hundred thousands column. 6 is at least 2, so subtract directly.
   6 - 2 = 4
7. Write the answer. Read the digits from the left, and put commas in.
   417,587

Check. Check: 268,860 + 417,587 = 686,447.

Watch out. When you exchange across zeros, change each zero to 9 as you pass it. Do not leave a zero in the middle.

Method. Subtract each column from the right. Exchange 1 from the column on the left when the top digit is too small.

1. Subtract the ones column. 1 is less than 2, so exchange 1 tens for 10 ones.
   11 - 2 = 9
2. Subtract the tens column. 3 is at least 3, so subtract directly.
   3 - 3 = 0
3. Subtract the hundreds column. 8 is at least 8, so subtract directly.
   8 - 8 = 0
4. Subtract the thousands column. 6 is at least 6, so subtract directly.
   6 - 6 = 0
5. Subtract the ten thousands column. 4 is at least 4, so subtract directly.
   4 - 4 = 0
6. Subtract the hundred thousands column. 7 is at least 6, so subtract directly.
   7 - 6 = 1
7. Write the answer. Read the digits from the left, and put commas in.
   100,009

Check. Check: 646,832 + 100,009 = 746,841.

Watch out. When you exchange across zeros, change each zero to 9 as you pass it. Do not leave a zero in the middle.

Method. Subtract each column from the right. Exchange 1 from the column on the left when the top digit is too small.

1. Subtract the ones column. 3 is less than 6, so exchange 1 tens for 10 ones.
   13 - 6 = 7
2. Subtract the tens column. 3 is less than 5, so exchange 1 hundreds for 10 tens.
   13 - 5 = 8
3. Subtract the hundreds column. 8 is at least 2, so subtract directly.
   8 - 2 = 6
4. Subtract the thousands column. 5 is less than 9, so exchange 1 ten thousands for 10 thousands.
   15 - 9 = 6
5. Subtract the ten thousands column. 4 is less than 5, so exchange 1 hundred thousands for 10 ten thousands.
   14 - 5 = 9
6. Subtract the hundred thousands column. 7 is at least 4, so subtract directly.
   7 - 4 = 3
7. Write the answer. Read the digits from the left, and put commas in.
   396,687

Check. Check: 459,256 + 396,687 = 855,943.

Watch out. When you exchange across zeros, change each zero to 9 as you pass it. Do not leave a zero in the middle.

Method. Subtract each column from the right. Exchange 1 from the column on the left when the top digit is too small.

1. Subtract the ones column. 0 is less than 8, so exchange 1 tens for 10 ones.
   10 - 8 = 2
2. Subtract the tens column. 6 is less than 8, so exchange 1 hundreds for 10 tens.
   16 - 8 = 8
3. Subtract the hundreds column. 0 is less than 6, so exchange 1 thousands for 10 hundreds.
   10 - 6 = 4
4. Subtract the thousands column. 5 is at least 2, so subtract directly.
   5 - 2 = 3
5. Subtract the ten thousands column. 5 is at least 4, so subtract directly.
   5 - 4 = 1
6. Subtract the hundred thousands column. 9 is at least 7, so subtract directly.
   9 - 7 = 2
7. Write the answer. Read the digits from the left, and put commas in.
   213,482

Check. Check: 742,688 + 213,482 = 956,170.

Watch out. When you exchange across zeros, change each zero to 9 as you pass it. Do not leave a zero in the middle.

Method. Subtract each column from the right. Exchange 1 from the column on the left when the top digit is too small.

1. Subtract the ones column. 1 is less than 9, so exchange 1 tens for 10 ones.
   11 - 9 = 2
2. Subtract the tens column. 1 is less than 2, so exchange 1 hundreds for 10 tens.
   11 - 2 = 9
3. Subtract the hundreds column. 4 is less than 9, so exchange 1 thousands for 10 hundreds.
   14 - 9 = 5
4. Subtract the thousands column. 4 is less than 9, so exchange 1 ten thousands for 10 thousands.
   14 - 9 = 5
5. Subtract the ten thousands column. 3 is less than 9, so exchange 1 hundred thousands for 10 ten thousands.
   13 - 9 = 4
6. Subtract the hundred thousands column. 4 is at least 4, so subtract directly.
   4 - 4 = 0
7. Write the answer. Read the digits from the left, and put commas in.
   45,592

Check. Check: 499,929 + 45,592 = 545,521.

Watch out. When you exchange across zeros, change each zero to 9 as you pass it. Do not leave a zero in the middle.

Method. Check by using the inverse: subtract for a sum, or add back for a difference.

1. Take one number away from the answer. If the sum is correct, taking one number away gives the other.
   688,072 - 569,853 = 118,219
2. Compare with the other number. Is 118,219 the same as 118,219?
   Same
3. Write Yes or No. Yes if the check works; No if it does not.
   Yes

Check. The correct answer is 688,072.

Watch out. A check that does not work means the answer is wrong. Find the mistake in the columns.

Method. Round each number first, then calculate with the rounded numbers.

1. Round the first number. Look at the thousands digit: 5 or more rounds up.
   236,844 is about 240,000
2. Round the second number. Use the same rule.
   314,998 is about 310,000
3. Add the rounded numbers. This is the estimate.
   240,000 + 310,000 = 550,000
4. Write the estimate. The exact answer should be close to this.
   550,000

Check. The exact answer is 551,842, which is close to 550,000.

Watch out. Estimate with the rounded numbers, then work out the exact answer with the column method.

Method. Check by using the inverse: subtract for a sum, or add back for a difference.

1. Take one number away from the answer. If the sum is correct, taking one number away gives the other.
   994,651 - 854,966 = 139,685
2. Compare with the other number. Is 139,685 the same as 139,685?
   Same
3. Write Yes or No. Yes if the check works; No if it does not.
   Yes

Check. The correct answer is 994,651.

Watch out. A check that does not work means the answer is wrong. Find the mistake in the columns.

Method. Check by using the inverse: subtract for a sum, or add back for a difference.

1. Take one number away from the answer. If the sum is correct, taking one number away gives the other.
   946,272 - 869,345 = 76,927
2. Compare with the other number. Is 76,927 the same as 75,927?
   Not the same
3. Write Yes or No. Yes if the check works; No if it does not.
   No

Check. The correct answer is 945,272.

Watch out. A check that does not work means the answer is wrong. Find the mistake in the columns.

Method. Round each number first, then calculate with the rounded numbers.

1. Round the first number. Look at the thousands digit: 5 or more rounds up.
   448,428 is about 450,000
2. Round the second number. Use the same rule.
   326,766 is about 330,000
3. Add the rounded numbers. This is the estimate.
   450,000 + 330,000 = 780,000
4. Write the estimate. The exact answer should be close to this.
   780,000

Check. The exact answer is 775,194, which is close to 780,000.

Watch out. Estimate with the rounded numbers, then work out the exact answer with the column method.

Method. Round each number first, then calculate with the rounded numbers.

1. Round the first number. Look at the thousands digit: 5 or more rounds up.
   459,919 is about 460,000
2. Round the second number. Use the same rule.
   25,866 is about 30,000
3. Add the rounded numbers. This is the estimate.
   460,000 + 30,000 = 490,000
4. Write the estimate. The exact answer should be close to this.
   490,000

Check. The exact answer is 485,785, which is close to 490,000.

Watch out. Estimate with the rounded numbers, then work out the exact answer with the column method.

Method. Check by using the inverse: subtract for a sum, or add back for a difference.

1. Take one number away from the answer. If the sum is correct, taking one number away gives the other.
   304,704 - 228,141 = 76,563
2. Compare with the other number. Is 76,563 the same as 76,573?
   Not the same
3. Write Yes or No. Yes if the check works; No if it does not.
   No

Check. The correct answer is 304,714.

Watch out. A check that does not work means the answer is wrong. Find the mistake in the columns.

Method. Check by using the inverse: subtract for a sum, or add back for a difference.

1. Take one number away from the answer. If the sum is correct, taking one number away gives the other.
   715,368 - 303,532 = 411,836
2. Compare with the other number. Is 411,836 the same as 401,836?
   Not the same
3. Write Yes or No. Yes if the check works; No if it does not.
   No

Check. The correct answer is 705,368.

Watch out. A check that does not work means the answer is wrong. Find the mistake in the columns.

Method. Check by using the inverse: subtract for a sum, or add back for a difference.

1. Take one number away from the answer. If the sum is correct, taking one number away gives the other.
   930,992 - 834,723 = 96,269
2. Compare with the other number. Is 96,269 the same as 106,269?
   Not the same
3. Write Yes or No. Yes if the check works; No if it does not.
   No

Check. The correct answer is 940,992.

Watch out. A check that does not work means the answer is wrong. Find the mistake in the columns.

Method. Check by using the inverse: subtract for a sum, or add back for a difference.

1. Take one number away from the answer. If the sum is correct, taking one number away gives the other.
   926,248 - 781,794 = 144,454
2. Compare with the other number. Is 144,454 the same as 134,454?
   Not the same
3. Write Yes or No. Yes if the check works; No if it does not.
   No

Check. The correct answer is 916,248.

Watch out. A check that does not work means the answer is wrong. Find the mistake in the columns.

Method. Check by using the inverse: subtract for a sum, or add back for a difference.

1. Take one number away from the answer. If the sum is correct, taking one number away gives the other.
   869,153 - 266,137 = 603,016
2. Compare with the other number. Is 603,016 the same as 603,016?
   Same
3. Write Yes or No. Yes if the check works; No if it does not.
   Yes

Check. The correct answer is 869,153.

Watch out. A check that does not work means the answer is wrong. Find the mistake in the columns.

Method. Check by using the inverse: subtract for a sum, or add back for a difference.

1. Take one number away from the answer. If the sum is correct, taking one number away gives the other.
   581,188 - 135,649 = 445,539
2. Compare with the other number. Is 445,539 the same as 455,539?
   Not the same
3. Write Yes or No. Yes if the check works; No if it does not.
   No

Check. The correct answer is 591,188.

Watch out. A check that does not work means the answer is wrong. Find the mistake in the columns.

Method. Check by using the inverse: subtract for a sum, or add back for a difference.

1. Take one number away from the answer. If the sum is correct, taking one number away gives the other.
   867,377 - 345,902 = 521,475
2. Compare with the other number. Is 521,475 the same as 521,475?
   Same
3. Write Yes or No. Yes if the check works; No if it does not.
   Yes

Check. The correct answer is 867,377.

Watch out. A check that does not work means the answer is wrong. Find the mistake in the columns.

Method. Check by using the inverse: subtract for a sum, or add back for a difference.

1. Take one number away from the answer. If the sum is correct, taking one number away gives the other.
   740,005 - 191,459 = 548,546
2. Compare with the other number. Is 548,546 the same as 548,546?
   Same
3. Write Yes or No. Yes if the check works; No if it does not.
   Yes

Check. The correct answer is 740,005.

Watch out. A check that does not work means the answer is wrong. Find the mistake in the columns.

Method. Round each number first, then calculate with the rounded numbers.

1. Round the first number. Look at the thousands digit: 5 or more rounds up.
   392,244 is about 390,000
2. Round the second number. Use the same rule.
   37,060 is about 40,000
3. Subtract the rounded numbers. This is the estimate.
   390,000 - 40,000 = 350,000
4. Write the estimate. The exact answer should be close to this.
   350,000

Check. The exact answer is 355,184, which is close to 350,000.

Watch out. Estimate with the rounded numbers, then work out the exact answer with the column method.

Method. Round each number first, then calculate with the rounded numbers.

1. Round the first number. Look at the thousands digit: 5 or more rounds up.
   363,966 is about 360,000
2. Round the second number. Use the same rule.
   191,116 is about 190,000
3. Add the rounded numbers. This is the estimate.
   360,000 + 190,000 = 550,000
4. Write the estimate. The exact answer should be close to this.
   550,000

Check. The exact answer is 555,082, which is close to 550,000.

Watch out. Estimate with the rounded numbers, then work out the exact answer with the column method.

Method. Work out the answer in the order the story happens, one step at a time.

1. Find the total picked. Add the two months together.
   194,973 + 222,088 = 417,061
2. Take away the apples sold. Subtract the apples that were sold.
   417,061 - 154,665 = 262,396
3. Write the answer. Check the answer makes sense in the story.
   262,396

Check. Check: the answer should fit the story; the numbers left are less than the start unless people or things came in.

Watch out. Read the whole problem first. Decide the operation for each step before you calculate.

Method. Use the inverse operation to find the missing number.

1. Think about the total. The missing number is what is left when we take the known number away.
   802,502 - 384,343
2. Subtract to find the missing number. Use the column method.
   802,502 - 384,343 = 418,159
3. Check by adding. The missing number and the known number must make the total.
   384,343 + 418,159 = 802,502
4. Write the missing number. This is the number in the box.
   418,159

Check. Check: put 418,159 into the sum and it works.

Watch out. To find a missing number in a sum, subtract. To find it in a difference, add.

Method. Use the inverse operation to find the missing number.

1. Think about the total. The missing number is what is left when we take the known number away.
   495,682 - 257,682
2. Subtract to find the missing number. Use the column method.
   495,682 - 257,682 = 238,000
3. Check by adding. The missing number and the known number must make the total.
   257,682 + 238,000 = 495,682
4. Write the missing number. This is the number in the box.
   238,000

Check. Check: put 238,000 into the sum and it works.

Watch out. To find a missing number in a sum, subtract. To find it in a difference, add.

Method. Use the inverse operation to find the missing number.

1. Add the number taken away to the answer. Adding undoes subtracting.
   83,088 + 37,426
2. Work out the sum. Use the column method.
   83,088 + 37,426 = 120,514
3. Check by subtracting. The answer must go back to the missing number.
   120,514 - 37,426 = 83,088
4. Write the missing number. This is the number in the box.
   120,514

Check. Check: put 120,514 into the sum and it works.

Watch out. To find a missing number in a sum, subtract. To find it in a difference, add.

Method. Use the inverse operation to find the missing number.

1. Think about the total. The missing number is what is left when we take the known number away.
   217,543 - 11,097
2. Subtract to find the missing number. Use the column method.
   217,543 - 11,097 = 206,446
3. Check by adding. The missing number and the known number must make the total.
   11,097 + 206,446 = 217,543
4. Write the missing number. This is the number in the box.
   206,446

Check. Check: put 206,446 into the sum and it works.

Watch out. To find a missing number in a sum, subtract. To find it in a difference, add.

Method. Use the inverse operation to find the missing number.

1. Think about the total. The missing number is what is left when we take the known number away.
   638,511 - 175,694
2. Subtract to find the missing number. Use the column method.
   638,511 - 175,694 = 462,817
3. Check by adding. The missing number and the known number must make the total.
   175,694 + 462,817 = 638,511
4. Write the missing number. This is the number in the box.
   462,817

Check. Check: put 462,817 into the sum and it works.

Watch out. To find a missing number in a sum, subtract. To find it in a difference, add.

Method. Use the inverse operation to find the missing number.

1. Think about the total. The missing number is what is left when we take the known number away.
   504,279 - 55,917
2. Subtract to find the missing number. Use the column method.
   504,279 - 55,917 = 448,362
3. Check by adding. The missing number and the known number must make the total.
   55,917 + 448,362 = 504,279
4. Write the missing number. This is the number in the box.
   448,362

Check. Check: put 448,362 into the sum and it works.

Watch out. To find a missing number in a sum, subtract. To find it in a difference, add.

Method. Use the inverse operation to find the missing number.

1. Add the number taken away to the answer. Adding undoes subtracting.
   249,478 + 110,200
2. Work out the sum. Use the column method.
   249,478 + 110,200 = 359,678
3. Check by subtracting. The answer must go back to the missing number.
   359,678 - 110,200 = 249,478
4. Write the missing number. This is the number in the box.
   359,678

Check. Check: put 359,678 into the sum and it works.

Watch out. To find a missing number in a sum, subtract. To find it in a difference, add.

Method. Use the inverse operation to find the missing number.

1. Think about the total. The missing number is what is left when we take the known number away.
   508,306 - 102,018
2. Subtract to find the missing number. Use the column method.
   508,306 - 102,018 = 406,288
3. Check by adding. The missing number and the known number must make the total.
   102,018 + 406,288 = 508,306
4. Write the missing number. This is the number in the box.
   406,288

Check. Check: put 406,288 into the sum and it works.

Watch out. To find a missing number in a sum, subtract. To find it in a difference, add.

Method. Use the inverse operation to find the missing number.

1. Think about the total. The missing number is what is left when we take the known number away.
   778,095 - 427,966
2. Subtract to find the missing number. Use the column method.
   778,095 - 427,966 = 350,129
3. Check by adding. The missing number and the known number must make the total.
   427,966 + 350,129 = 778,095
4. Write the missing number. This is the number in the box.
   350,129

Check. Check: put 350,129 into the sum and it works.

Watch out. To find a missing number in a sum, subtract. To find it in a difference, add.

Method. Use the inverse operation to find the missing number.

1. Add the number taken away to the answer. Adding undoes subtracting.
   340,542 + 281,988
2. Work out the sum. Use the column method.
   340,542 + 281,988 = 622,530
3. Check by subtracting. The answer must go back to the missing number.
   622,530 - 281,988 = 340,542
4. Write the missing number. This is the number in the box.
   622,530

Check. Check: put 622,530 into the sum and it works.

Watch out. To find a missing number in a sum, subtract. To find it in a difference, add.

Method. Use the inverse operation to find the missing number.

1. Add the number taken away to the answer. Adding undoes subtracting.
   346,409 + 78,701
2. Work out the sum. Use the column method.
   346,409 + 78,701 = 425,110
3. Check by subtracting. The answer must go back to the missing number.
   425,110 - 78,701 = 346,409
4. Write the missing number. This is the number in the box.
   425,110

Check. Check: put 425,110 into the sum and it works.

Watch out. To find a missing number in a sum, subtract. To find it in a difference, add.

Method. Use the inverse operation to find the missing number.

1. Think about the total. The missing number is what is left when we take the known number away.
   748,123 - 255,684
2. Subtract to find the missing number. Use the column method.
   748,123 - 255,684 = 492,439
3. Check by adding. The missing number and the known number must make the total.
   255,684 + 492,439 = 748,123
4. Write the missing number. This is the number in the box.
   492,439

Check. Check: put 492,439 into the sum and it works.

Watch out. To find a missing number in a sum, subtract. To find it in a difference, add.

Method. Work out the answer in the order the story happens, one step at a time.

1. Work out the people left after some moved away. Take away the people who moved away.
   499,278 - 193,221 = 306,057
2. Add the people who moved in. Add the new people to the number left.
   306,057 + 81,406 = 387,463
3. Write the answer. Check the answer makes sense in the story.
   387,463

Check. Check: the answer should fit the story; the numbers left are less than the start unless people or things came in.

Watch out. Read the whole problem first. Decide the operation for each step before you calculate.

Method. Use the inverse operation to find the missing number.

1. Add the number taken away to the answer. Adding undoes subtracting.
   476,717 + 45,129
2. Work out the sum. Use the column method.
   476,717 + 45,129 = 521,846
3. Check by subtracting. The answer must go back to the missing number.
   521,846 - 45,129 = 476,717
4. Write the missing number. This is the number in the box.
   521,846

Check. Check: put 521,846 into the sum and it works.

Watch out. To find a missing number in a sum, subtract. To find it in a difference, add.

Method. Use the inverse operation to find the missing number.

1. Think about the total. The missing number is what is left when we take the known number away.
   486,234 - 141,505
2. Subtract to find the missing number. Use the column method.
   486,234 - 141,505 = 344,729
3. Check by adding. The missing number and the known number must make the total.
   141,505 + 344,729 = 486,234
4. Write the missing number. This is the number in the box.
   344,729

Check. Check: put 344,729 into the sum and it works.

Watch out. To find a missing number in a sum, subtract. To find it in a difference, add.

Method. Subtract each column from the right. Exchange 1 from the column on the left when the top digit is too small.

1. Subtract the ones column. 8 is at least 3, so subtract directly.
   8 - 3 = 5
2. Subtract the tens column. 6 is at least 2, so subtract directly.
   6 - 2 = 4
3. Subtract the hundreds column. 2 is less than 4, so exchange 1 thousands for 10 hundreds.
   12 - 4 = 8
4. Subtract the thousands column. 7 is at least 5, so subtract directly.
   7 - 5 = 2
5. Subtract the ten thousands column. 3 is less than 9, so exchange 1 hundred thousands for 10 ten thousands.
   13 - 9 = 4
6. Subtract the hundred thousands column. 0 is at least 0, so subtract directly.
   0 - 0 = 0
7. Write the answer. Read the digits from the left, and put commas in.
   42,845

Check. Check: 95,423 + 42,845 = 138,268.

Watch out. When you exchange across zeros, change each zero to 9 as you pass it. Do not leave a zero in the middle.

Method. Use the inverse operation to find the missing number.

1. Think about the total. The missing number is what is left when we take the known number away.
   604,641 - 258,175
2. Subtract to find the missing number. Use the column method.
   604,641 - 258,175 = 346,466
3. Check by adding. The missing number and the known number must make the total.
   258,175 + 346,466 = 604,641
4. Write the missing number. This is the number in the box.
   346,466

Check. Check: put 346,466 into the sum and it works.

Watch out. To find a missing number in a sum, subtract. To find it in a difference, add.

Method. Check by using the inverse: subtract for a sum, or add back for a difference.

1. Take one number away from the answer. If the sum is correct, taking one number away gives the other.
   575,432 - 442,296 = 133,136
2. Compare with the other number. Is 133,136 the same as 133,146?
   Not the same
3. Write Yes or No. Yes if the check works; No if it does not.
   No

Check. The correct answer is 575,442.

Watch out. A check that does not work means the answer is wrong. Find the mistake in the columns.

Method. Subtract each column from the right. Exchange 1 from the column on the left when the top digit is too small.

1. Subtract the ones column. 5 is less than 9, so exchange 1 tens for 10 ones.
   15 - 9 = 6
2. Subtract the tens column. 3 is less than 9, so exchange 1 hundreds for 10 tens.
   13 - 9 = 4
3. Subtract the hundreds column. 6 is at least 3, so subtract directly.
   6 - 3 = 3
4. Subtract the thousands column. 3 is less than 6, so exchange 1 ten thousands for 10 thousands.
   13 - 6 = 7
5. Subtract the ten thousands column. 3 is at least 2, so subtract directly.
   3 - 2 = 1
6. Subtract the hundred thousands column. 5 is at least 3, so subtract directly.
   5 - 3 = 2
7. Write the answer. Read the digits from the left, and put commas in.
   217,346

Check. Check: 326,399 + 217,346 = 543,745.

Watch out. When you exchange across zeros, change each zero to 9 as you pass it. Do not leave a zero in the middle.

Method. Use the inverse operation to find the missing number.

1. Add the number taken away to the answer. Adding undoes subtracting.
   338,690 + 211,998
2. Work out the sum. Use the column method.
   338,690 + 211,998 = 550,688
3. Check by subtracting. The answer must go back to the missing number.
   550,688 - 211,998 = 338,690
4. Write the missing number. This is the number in the box.
   550,688

Check. Check: put 550,688 into the sum and it works.

Watch out. To find a missing number in a sum, subtract. To find it in a difference, add.

Method. Use the inverse operation to find the missing number.

1. Think about the total. The missing number is what is left when we take the known number away.
   409,082 - 102,640
2. Subtract to find the missing number. Use the column method.
   409,082 - 102,640 = 306,442
3. Check by adding. The missing number and the known number must make the total.
   102,640 + 306,442 = 409,082
4. Write the missing number. This is the number in the box.
   306,442

Check. Check: put 306,442 into the sum and it works.

Watch out. To find a missing number in a sum, subtract. To find it in a difference, add.

Method. Add the columns from the right. Carry any ten into the next column on the left.

1. Add the ones column. Write 7 in the ones column.
   1 + 6 = 7
2. Add the tens column. Write 3 and carry 1 to the hundreds column.
   5 + 8 = 13
3. Add the hundreds column. Write 9 and carry 1 to the thousands column.
   9 + 9 + 1 carried = 19
4. Add the thousands column. Write 0 and carry 1 to the ten thousands column.
   9 + 0 + 1 carried = 10
5. Add the ten thousands column. Write 4 and carry 1 to the hundred thousands column.
   8 + 5 + 1 carried = 14
6. Add the hundred thousands column. Write 9 in the hundred thousands column.
   8 + 0 + 1 carried = 9
7. Write the answer. Put the digits together, with commas between groups of three.
   940,937

Check. Check: 940,937 - 50,986 = 889,951.

Watch out. Carry the 1 into the next column. Do not forget it, and do not write it as a digit in its own column.

Method. Subtract each column from the right. Exchange 1 from the column on the left when the top digit is too small.

1. Subtract the ones column. 8 is at least 5, so subtract directly.
   8 - 5 = 3
2. Subtract the tens column. 7 is less than 9, so exchange 1 hundreds for 10 tens.
   17 - 9 = 8
3. Subtract the hundreds column. 3 is less than 8, so exchange 1 thousands for 10 hundreds.
   13 - 8 = 5
4. Subtract the thousands column. 7 is less than 8, so exchange 1 ten thousands for 10 thousands.
   17 - 8 = 9
5. Subtract the ten thousands column. 5 is at least 3, so subtract directly.
   5 - 3 = 2
6. Subtract the hundred thousands column. 4 is at least 0, so subtract directly.
   4 - 0 = 4
7. Write the answer. Read the digits from the left, and put commas in.
   429,583

Check. Check: 38,895 + 429,583 = 468,478.

Watch out. When you exchange across zeros, change each zero to 9 as you pass it. Do not leave a zero in the middle.

Method. Add the columns from the right. Carry any ten into the next column on the left.

1. Add the ones column. Write 0 and carry 1 to the tens column.
   7 + 3 = 10
2. Add the tens column. Write 5 in the tens column.
   2 + 2 + 1 carried = 5
3. Add the hundreds column. Write 3 and carry 1 to the thousands column.
   4 + 9 = 13
4. Add the thousands column. Write 7 in the thousands column.
   4 + 2 + 1 carried = 7
5. Add the ten thousands column. Write 9 in the ten thousands column.
   9 + 0 = 9
6. Add the hundred thousands column. Write 4 in the hundred thousands column.
   0 + 4 = 4
7. Write the answer. Put the digits together, with commas between groups of three.
   497,350

Check. Check: 497,350 - 402,923 = 94,427.

Watch out. Carry the 1 into the next column. Do not forget it, and do not write it as a digit in its own column.

Method. Subtract each column from the right. Exchange 1 from the column on the left when the top digit is too small.

1. Subtract the ones column. 3 is less than 5, so exchange 1 tens for 10 ones.
   13 - 5 = 8
2. Subtract the tens column. 2 is at least 2, so subtract directly.
   2 - 2 = 0
3. Subtract the hundreds column. 2 is less than 6, so exchange 1 thousands for 10 hundreds.
   12 - 6 = 6
4. Subtract the thousands column. 1 is at least 1, so subtract directly.
   1 - 1 = 0
5. Subtract the ten thousands column. 7 is at least 4, so subtract directly.
   7 - 4 = 3
6. Subtract the hundred thousands column. 7 is at least 1, so subtract directly.
   7 - 1 = 6
7. Write the answer. Read the digits from the left, and put commas in.
   630,608

Check. Check: 141,625 + 630,608 = 772,233.

Watch out. When you exchange across zeros, change each zero to 9 as you pass it. Do not leave a zero in the middle.

Method. Round each number first, then calculate with the rounded numbers.

1. Round the first number. Look at the thousands digit: 5 or more rounds up.
   249,766 is about 250,000
2. Round the second number. Use the same rule.
   351,138 is about 350,000
3. Add the rounded numbers. This is the estimate.
   250,000 + 350,000 = 600,000
4. Write the estimate. The exact answer should be close to this.
   600,000

Check. The exact answer is 600,904, which is close to 600,000.

Watch out. Estimate with the rounded numbers, then work out the exact answer with the column method.

Method. Add the columns from the right. Carry any ten into the next column on the left.

1. Add the ones column. Write 6 in the ones column.
   5 + 1 = 6
2. Add the tens column. Write 1 and carry 1 to the hundreds column.
   5 + 6 = 11
3. Add the hundreds column. Write 8 in the hundreds column.
   4 + 3 + 1 carried = 8
4. Add the thousands column. Write 9 in the thousands column.
   6 + 3 = 9
5. Add the ten thousands column. Write 4 and carry 1 to the hundred thousands column.
   7 + 7 = 14
6. Add the hundred thousands column. Write 9 in the hundred thousands column.
   5 + 3 + 1 carried = 9
7. Write the answer. Put the digits together, with commas between groups of three.
   949,816

Check. Check: 949,816 - 373,361 = 576,455.

Watch out. Carry the 1 into the next column. Do not forget it, and do not write it as a digit in its own column.

Method. Subtract each column from the right. Exchange 1 from the column on the left when the top digit is too small.

1. Subtract the ones column. 1 is at least 1, so subtract directly.
   1 - 1 = 0
2. Subtract the tens column. 4 is at least 2, so subtract directly.
   4 - 2 = 2
3. Subtract the hundreds column. 4 is at least 0, so subtract directly.
   4 - 0 = 4
4. Subtract the thousands column. 7 is less than 9, so exchange 1 ten thousands for 10 thousands.
   17 - 9 = 8
5. Subtract the ten thousands column. 0 is less than 1, so exchange 1 hundred thousands for 10 ten thousands.
   10 - 1 = 9
6. Subtract the hundred thousands column. 7 is at least 1, so subtract directly.
   7 - 1 = 6
7. Write the answer. Read the digits from the left, and put commas in.
   698,420

Check. Check: 119,021 + 698,420 = 817,441.

Watch out. When you exchange across zeros, change each zero to 9 as you pass it. Do not leave a zero in the middle.

Method. Add the columns from the right. Carry any ten into the next column on the left.

1. Add the ones column. Write 9 in the ones column.
   5 + 4 = 9
2. Add the tens column. Write 6 in the tens column.
   3 + 3 = 6
3. Add the hundreds column. Write 3 and carry 1 to the thousands column.
   4 + 9 = 13
4. Add the thousands column. Write 0 and carry 1 to the ten thousands column.
   3 + 6 + 1 carried = 10
5. Add the ten thousands column. Write 8 in the ten thousands column.
   7 + 0 + 1 carried = 8
6. Add the hundred thousands column. Write 9 in the hundred thousands column.
   8 + 1 = 9
7. Write the answer. Put the digits together, with commas between groups of three.
   980,369

Check. Check: 980,369 - 106,934 = 873,435.

Watch out. Carry the 1 into the next column. Do not forget it, and do not write it as a digit in its own column.

Method. Add the columns from the right. Carry any ten into the next column on the left.

1. Add the ones column. Write 7 in the ones column.
   6 + 1 = 7
2. Add the tens column. Write 7 and carry 1 to the hundreds column.
   9 + 8 = 17
3. Add the hundreds column. Write 4 in the hundreds column.
   2 + 1 + 1 carried = 4
4. Add the thousands column. Write 2 and carry 1 to the ten thousands column.
   8 + 4 = 12
5. Add the ten thousands column. Write 8 in the ten thousands column.
   5 + 2 + 1 carried = 8
6. Add the hundred thousands column. Write 5 in the hundred thousands column.
   4 + 1 = 5
7. Write the answer. Put the digits together, with commas between groups of three.
   582,477

Check. Check: 582,477 - 124,181 = 458,296.

Watch out. Carry the 1 into the next column. Do not forget it, and do not write it as a digit in its own column.

Method. Subtract each column from the right. Exchange 1 from the column on the left when the top digit is too small.

1. Subtract the ones column. 4 is less than 7, so exchange 1 tens for 10 ones.
   14 - 7 = 7
2. Subtract the tens column. 1 is less than 3, so exchange 1 hundreds for 10 tens.
   11 - 3 = 8
3. Subtract the hundreds column. 7 is at least 2, so subtract directly.
   7 - 2 = 5
4. Subtract the thousands column. 9 is at least 5, so subtract directly.
   9 - 5 = 4
5. Subtract the ten thousands column. 8 is at least 4, so subtract directly.
   8 - 4 = 4
6. Subtract the hundred thousands column. 1 is at least 0, so subtract directly.
   1 - 0 = 1
7. Write the answer. Read the digits from the left, and put commas in.
   144,587

Check. Check: 45,237 + 144,587 = 189,824.

Watch out. When you exchange across zeros, change each zero to 9 as you pass it. Do not leave a zero in the middle.

Method. Subtract each column from the right. Exchange 1 from the column on the left when the top digit is too small.

1. Subtract the ones column. 4 is less than 8, so exchange 1 tens for 10 ones.
   14 - 8 = 6
2. Subtract the tens column. 1 is less than 3, so exchange 1 hundreds for 10 tens.
   11 - 3 = 8
3. Subtract the hundreds column. 3 is less than 4, so exchange 1 thousands for 10 hundreds.
   13 - 4 = 9
4. Subtract the thousands column. 5 is at least 0, so subtract directly.
   5 - 0 = 5
5. Subtract the ten thousands column. 7 is at least 3, so subtract directly.
   7 - 3 = 4
6. Subtract the hundred thousands column. 9 is at least 3, so subtract directly.
   9 - 3 = 6
7. Write the answer. Read the digits from the left, and put commas in.
   645,986

Check. Check: 330,438 + 645,986 = 976,424.

Watch out. When you exchange across zeros, change each zero to 9 as you pass it. Do not leave a zero in the middle.

Method. Check by using the inverse: subtract for a sum, or add back for a difference.

1. Take one number away from the answer. If the sum is correct, taking one number away gives the other.
   845,615 - 633,340 = 212,275
2. Compare with the other number. Is 212,275 the same as 211,275?
   Not the same
3. Write Yes or No. Yes if the check works; No if it does not.
   No

Check. The correct answer is 844,615.

Watch out. A check that does not work means the answer is wrong. Find the mistake in the columns.

Method. Use the inverse operation to find the missing number.

1. Think about the total. The missing number is what is left when we take the known number away.
   494,697 - 460,804
2. Subtract to find the missing number. Use the column method.
   494,697 - 460,804 = 33,893
3. Check by adding. The missing number and the known number must make the total.
   460,804 + 33,893 = 494,697
4. Write the missing number. This is the number in the box.
   33,893

Check. Check: put 33,893 into the sum and it works.

Watch out. To find a missing number in a sum, subtract. To find it in a difference, add.

Method. Use the inverse operation to find the missing number.

1. Think about the total. The missing number is what is left when we take the known number away.
   539,434 - 351,316
2. Subtract to find the missing number. Use the column method.
   539,434 - 351,316 = 188,118
3. Check by adding. The missing number and the known number must make the total.
   351,316 + 188,118 = 539,434
4. Write the missing number. This is the number in the box.
   188,118

Check. Check: put 188,118 into the sum and it works.

Watch out. To find a missing number in a sum, subtract. To find it in a difference, add.